Safety device for projectile fuses



Dec. 12, 1939. HNER 2,183,073

SAFETY DEVICE FOR PROJECTILE FUSES Filed June 28, 1958 2 Sheets-Sheet 1 5:92. la l0 ,4 i

` 1.4:?. ,2 INVENTOR GUIDO HN G E R 1 q y? v ATTYs Dee. 12, 1939. G. HNGR 2,183,073

SAFETY DEVIGE FOR PROJECTILE FUSES Filed June 28, 193B' 2vShetS-Sheet 2 lNvENToR Guano HNGER 8W, www? f www ATTYS.

Patented Dec. 12, 1939 orties SAFETY DEVICE Foa PROJECTILE FUsEs Guido Hnger, Geneva, Switzerland, assigner to Mina S. A., Binningen, Switzerland, a corporation of Switzerland Application June 28, 1938, Serial No. 216,403

In Switzerland June 30, 1937 9 Claims.

rlIhis invention relates in general to projectile fuses and more particularly has reference to a clockwork controlled safety device.

The use of clockwork in projectile fuses to convtrol or to directly actuate safety means of all kinds' is generally known, as is also the use of spring force as a drive in such fuse clockwork mechanisms.

On the other hand, difficulties are encountered in meeting'the requirements for extremely inexpensive, simple, and at the same time small clockwork of great precision of operation, whereby in hand grenades, for example, of given dimensions and weights, there will be available a maximum space for the explosive charge, these requirements being mutually contradictory.

In view of these requirements, the attempts of manufacturers have been directed to provide clockwork which will be loaded as little' as pos- -sible by the operations which it has tor perform, whereby clockwork of small dimensions and of small driving torque can be used, and also to enable the precision of operation of the clockwork to be as great as possible.

The object of the present invention is to provide a supplementary safety means, completely independent of all the usual safety means present in projectiles, which supplementary safety means comes into action only when for any rea- 30sson the course of the firing operation does not proceed normally-that is, in the prescribed manner. This safety means consists of a device which permits the ignition of the bursting charge only at and during an exactly predetermined time, independently of other safety means, and without influencing the ignition means or being influenced by such means as long as the projectile explodes at the desired time and place. In all normal cases in which the safety means doesnot have to operate, there is therefore no interference whatever with the ignition means.

The safety means according to this invention consists of a closure member not inuenced by the ignition means and driven by a clockwork, which closure means, for example, blocks the path of the ring pin to the detonator, or obstructs the firing channel between the detonator and the bursting charge at a suitable point, and

which leaves said pin or channel free for operation only at and during a predetermined time calculated from the instant of beginning of projectne night.

Several constructions of the safety means according to the present invention are illustrated by way of example in the accompanying draw ings, in which:

Figure 1 is a plan and partial sectional View of a device according to the present invention.

Fig. 2 is a vertical sectional view on line II-II 5 of Fig. l.

Fig. 3 is a vertical section similar to Fig. 2 of a modiiication.

Fig. 4 is a plan View, partly in section,v of another modification.

Fig. 5 is a sectional view on line V-V of Fig. 4.

Similar reference characters denote corresponding parts in all the iiguresv of the drawings.

The clockwork mechanism of the present invention enclosed in a body I9 is adapted to be mounted in the usual manner between two parts 2I and 22 of a fuse body. As shown in Figs. 1 and 2, a rotatable closure member I6 is mounted to close or block the path oi-a firing pin I to prevent contact of the latter with a cap I I. Closure member I6 is rotated during operation of the mechanism by a helical Spring I2 surrounding the spindle 24 of the member IS, one end of the spring being anchored to the body I9 of the clockwork and the other end being secured to the member I6.

Gear teeth 25 are provided on the periphery of member IB and mesh with the teeth of a pinion 26 xed on a common shaft with an escapement Wheel I5. A rocker I3 of the clockwork escapement cooperates with the escapement wheel I5. A sickle-shaped rocking lever I4 is xed to the rocker I3 and swings in a cavity I8 of the body I9. Closure member I6 has an arcuate-shaped opening Il of suitable size for the purpose of permitting the ignition of the bursting chargev during a predetermined time. l

The operation is as follows:

-The clockworkvmechanism, preferably wound up during the assembly of the fuse, is secured in any known manner against premature operation. At the instant of ring of the projectile, the

clockwork is released by a safety means (not illustrated), and the clockwork and closure member I6, which heretofore by its position renderedignition on the brusting charge impossible, start motion at a speed determined only by the pin iD, which free path is preserved during a time which can also be freely determined in the manufacture of the mechanism.

If, during this period, corresponding to the length of the opening l1, ignition does not take place for any reason, for example, due to failure of other safety devices, then the closure member will again obstruct the path of movement of they firing pin so that a subsequent undesired explosion of the projectile is impossible.

This re-locking of the ring pin, which cannot be released from outside, possesses a'great value, particularly in the case of hand grenades, since it prevents any non-exploded grenades thrown back by the enemy, doing damage to friendly troops,

In the modiiication according` to Fig.' 3, the closure member i6, instead of obstructing the path of movement of a firing pin, obstructs a re channel 23 between a cap il and a detonator 20.

It is clear that in the special case where relocking is not desired, the opening Il must be made such that the path or" the firing pin to the detonator mustv still remain open after complete .running down of the clockwork." This corresponds to the special case in which the predetermined period of opening is endless. In similar manner, it can be arranged that the firing channel in the modification of Fig. 3 can be kept permanently opened at the end of a predetermined time calculated from the launching of the projectile.

As regards the drive of the clockwork for actuating the safety device, this canbe eiected in known manner by spring power, and in the case of projectiles with spin motion, it can be effected by centrifugal force.

In the construction according to Fig. 4, the ring pin lil alsoV serves as the shaft of the escapement i3, the rocking lever in this case having the form of a circular disc I4.

A special shaping of the rocking lever, for eX- ample, as shown in Figs. l and 4, is important in order that notwithstanding small dimensions of the clockwork, long periods of rocking with small amplitude of rocking can be obtained. These requirements are the more important, since the mechanical work which canl be stored in a relatively small driving spring, without appreciable time fatigue, is also very small, so that it is necessary for the number of escapement oscillations during the whole running period of the clockwork to be very few.

It is obvious that the herein described constructions and details may be modified without departing from the invention. For example, the closure member, instead of being rotary, may have a straight line motion.

The herein described safety means according to the invention has the great advantage of being independent of the speed of flight ofthe projectile, of rotation oi the projectile, and in particular independent ci the ballistic factors, and it provides a re-locking mechanism which will make projected, but not destroyed, projectiles safe to handle. Obviously, it can be used in all fuses, whether impact or time fuses, or artillery weapons, aerial bombs, hand grenades, or projectiles of trench mortars, since the safety means according to the present invention operates entirely separately from all other safety means.

I claim:

l. In a projectile fuse having a path for access to a bursting charge, a clockwork actuated safety device comprising a closure member interposed in aisaovs and closing said path for preventing access to said bursting charge, said closure member having an opening therein, means for displacing said closure member through a position wherein the opening will register with said path to permit access through said path to the bursting charge to a position wherein the path will again be closed,

.and clockwork mechanism for timing the displacement of said closure member.

2. In a projectile fuse having a path for access to a bursting charge, a clockwork actuated safety device comprising a Yrotatable disc-like closure member interposed in and closing said path for preventing access to said bursting charge, said closulemember having an opening therein adapted to register with said path when said closure member is rotatedto a predetermined position, a spring for rotating said closure member through the position wherein the opening registers with said path to a position wherein said path is again closed,` and clockwork mechanism for vtiming the rotation of said closure member.

3. In a projectile fuse having a detonator and a iring pin, a clockwork controlled safety device comprising a closure member interposed in and blocking the pat-h of travel of the ring pin between the detonator and firing pin, said closure member having an opening therein, means for displacingv said closure member to and through a position to permit access of the firing pin to the detonator through said opening to a position to again block said path, and clockwork mechanism for controlling the displacement of said closure member.

4., In a projectile fuse having a detonator and a firing pin, a clockwork controlled safety device comprising a rotary closure member interposed in and blocking the path of travel of the firing pin between the detonator and ring pin, said rotary closure member having an opening therein adapted to register with the path of travel of the firing pin when the closure member is in a predetermined. positionmeans for rotatingsaid closure member to and through saidl predetermined position to. a position again blocking said path, and clockwork mechanism for controlling the rotation of said member.

5. In a projectile fuse having a detonator and a firing pin, a clockwork controlled safety device comprising a rotary closure member interposed in and blocking the path. of travell of the firing pin between the detonator and firing pin, said rotary closure member having an opening therein adapted to register with the path of travel of the firing pin when the closure member is in a predetermined position, means for rotating said closure member to and through said predetermined position to a position again bloclnng said path, an escapement wheel,v means for transmitting rotationl of the closure member to the escapem'ent wheel, an escapement rocker associated with the escapement wheel, and a sickle-shaped rocking lever carried by said rocker.

6. In aprojectile fuse having a detonator and a ring pin, a clockworkl controlled safety device comprising a rotary closure member interposed in the path of travel of the firing pin between the detonator and ring pin, said rotary closure member havingan opening therein adapted to register with the path of travel of the iring pin when the closure member is in a predetermined position, means for rotating said closure member to and through said predetermined position to a position again'blocking said path, a cylindrical clockwork casingysaid rotary closure member being mounted 2,183,073 eccentrically in said casing, and escapement Wheel, means for transmitting rotation of the closure member to the escapement wheel, an

escapement rocker mounted eccentrically of and adjacent the periphery of the casing, said casing having a free space opposite the rocker, and a vsickle-shaped rocker lever mounted on said rocker and having its blade-like portion extending into said free space.

7. In a projectile fuse having a detonator and a firing pin, a clockwork controlled safety device comprising a rotary closure'member interposedin and blocking the path of travel of the ring pin between the detonator and firing pin, said rotary closure member having an opening therein adapted to register With the path of travel of the ring pin When the closure member is in a pre-kr a ring pin, a clockwork controlled safety device comprising a rotary closure member interposed in and blocking the pathof travel of the firing pin between the detonator and firing pin, said rotary. closure member having an opening therein adapt-` ed to register with'the path of travel of the firing p pinWhen the closure member is in a predetermined position, means or rotating said closure member to and through said predetermined position to a position again blocking said path, a cylindrical clockwork casing, said rotaryclosure member being mounted eccentrically in said casf ing, an escapement wheel, means for transmitting rotation of the closure member to the escapement Wheel, an escapement rocker mounted on the firing pin, and a circulardisc-like rocker lever carried by said rocker.

.3. In a projectile fuse, a detonator, a cap, a re channel between Isaid detonator andcap, a. clockwork actuated safety device comprising a closure member interposed in said re channel -for closing the same, a spring for displacing said closure member to and through a position to open said channel to a position to'again close said channel, and clockwork ymechanism for timing the `displacement of said closure member.I

GUIDO HNGrER. 

